Worked on the elastic/elastic-agent repository to enhance packaging reliability by enforcing the PACKAGES environment variable during the build process. Addressed a packaging bug in Go by introducing explicit error messaging when PACKAGES was unset, preventing silent defaults and ensuring consistent behavior across environments. Added support for PACKAGES=all to streamline selection of all package types, and refactored key type definitions into a dedicated module for improved maintainability. Updated documentation to clearly communicate the new configuration requirements and user experience implications. This backend development work focused on making packaging behavior explicit, reducing support overhead, and improving clarity for both users and maintainers.